In view of the importance of sealing properties (liquid leakage resistance), elastic bodies such as rubber are used in parts which slide while maintaining their sealing performance, for example a gasket which is integrated with a syringe plunger and forms a seal between the plunger and barrel. Unfortunately, such elastic bodies have a slight problem with the sliding properties (see Patent Literature 1). Thus, a sliding property improving agent, for example silicone oil, is applied to the sliding surface. However, a concern has been raised over the potential adverse effects of silicone oil on recently marketed bio-preparations. On the other hand, gaskets not coated with a sliding property improving agent have poor sliding properties and thus do not allow plungers to be smoothly pushed but cause them to pulsate during administration, leading to problems such as inaccurate injection amount and infliction of pain on patients.
To satisfy the conflicting requirements, sealing properties and sliding properties, a coating technique using a self-lubricating PTFE film has been proposed (see Patent Literature 2). Unfortunately, such PTFE films are generally expensive and increase the production cost of processed products. Thus, the range of applications of these films is limited. Also, products coated with PTFE films might not be reliable when they are used in applications where sliding or the like is repeated and thus durability is required. Furthermore, since PTFE is vulnerable to radiation, the PTFE-coated products unfortunately cannot be sterilized by radiation.
Consideration may also be given to the use in other applications where sliding properties are required in the presence of water. Specifically, water can be delivered without a loss by reducing the fluid resistance of the inner surface of a pre-filled syringe or of the inner surface of a pipe or tube for delivering water, or by increasing or markedly reducing the contact angle with water. Reduction in the surface resistance of the internal/external surfaces of a catheter tube facilitates insertion of the catheter into the body or introduction of a guide wire through the catheter. Drainage of water on wet roads and of snow on snowy roads can be improved by reducing the fluid resistance of the groove surfaces of tires, or by increasing or markedly reducing the contact angle with water. This results in enhanced grip performance and improved hydroplaning performance and therefore better safety. In addition, less adhesion of dirt and dusts can be expected when the sliding resistance of the sidewall surfaces of tires or the walls of buildings is reduced, or when their contact angle with water is increased.
Further advantageous effects can be expected, including, for example: less pressure loss upon delivering water, an aqueous solution or the like through a diaphragm such as a diaphragm pump or valve; easy sliding of skis and snowboards achieved by enhancing the sliding properties of the sliding surfaces thereof; better noticeability of road signs and signboards achieved by enhancing the sliding properties thereof to allow snow to readily slide on the surface; reduction in water resistance or drag on the outer peripheries of ships and less adhesion of bacteria on the outer peripheries, achieved by reducing the sliding resistance of the outer peripheries or by increasing the contact angle with water; and reduction in water resistance or drag of swimsuits achieved by improving the sliding properties of the thread surfaces thereof.